Plan step 35: the Layout section gains a working example of list-detail,
supporting pane and feed, and one of surfaces, stacks, rows and grids,
written with the layout components and md-* text classes only; the panes
table names <x-list-detail> and <x-supporting-pane>. The showcase's own
Tailwind stays for step 38.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9